Technical Abstract:
Manure application methods can change the nature of P transport. Rainfall simulation experiments using the National P Research Project protocol and column leaching experiments using 30-cm diameter intact soil columns (50-cm deep) were conducted to assess the effects of broadcasting or incorporating of dairy manure on the fate of P in overland and subsurface flow from two soils. Incorporation of manure into the soil significantly decreased dissolved P losses in both overland and subsurface flow relative to broadcasting manure, with the magnitude of the difference modified by soil. For the finer textured soil, dissolved P losses from the incorporated treatment were not significantly different from the unamended control. Even so, because manure incorporation increased erosion of soil and manure particles, total P losses from broadcast and incorporated dairy manure treatments were similar. Results highlight the trade-offs in manure management options to control agricultural P losses.